Desk-lock.



No. 739,407. I PATBNTED SEPT. 22, 1903. A. R; FERGUSSON.

DESK LOCK.

APPLICATION FILED SEPT. 6, 1902.

N0 MODEL.

Patented September 22, 1903.

PATENT #OFFICE.

ALAN ROBB FERGUSSON, OF NEW YORK, N. Y.

DESK- LOCK.

SPECIFICATION forming part ofLettersPatent No. 739,407, dated September. 22,1903.

Applicationfiled September 6,1902. Serial no. 122,295. No model.)

To aZZ whom it may concern:

Be it known that I,ALA N RoBB FEReUs'son,

a citizen of the United States, residing in New York, in the county of New Yo rk and State 5 of New York, have invented certain new and useful Improvements inDesk-Locks, of which the following is a specification- I v The present invention relates to locks for desks,more particularly to roll-top desks, and especially to looks such as described in my Patent Reissue No. 11,949, dated November 26, 1901.

It is desirable in desk-locks for roll-top desks to lock both sides of the roll-top to the sides of the desk,- but arrange the lock in such a manner that by simply closing the top the locking-bolts will enter the keeper. It is furthermore very desirable to 'have the key ejected automatically, so that the same cannot be bent or broken E if accidentally left in the keyhole.

The accompanying drawings,formin g a part of the present application, illustrate the new lock in its preferred form.

of a roll-top desk, showing the new locking mechanism Fig. 2, a perspective view of the locking device; Fig. 3, a longitudinal crosssection ofthe key-operated parts; Fig. 4, a perspective view of the rotary tumblers; Fig. 5, a side view of the returning-springs; Fig. 6, a perspective View of a part of the casing; Fig. 7, a view of the key, and Figs. 8 and 9 views of a safety device. 35 Similar characters ofreference indicate corresponding parts throughout i the several views. I

1 and 2 in Fig. 2 are sliding bolts provided with tubular bolt-heads 3 and 4. Each boltceiving a pin 7 and 8, passing transversely through the bolts 1 and 2. Coiled springs 9 and 10 press against the bolt-heads 3 and 4 and against upturned ears of stationary plates 11 and 12 andhold the bolt-heads 3 4 in their outermost position. Plates 11 and 12 are provided with slots 13 and 14 for receiving pins 15 and 16, passing transversely through bolts 1 and 2 and preventing turning of the bolts. 50 'The key-operated mechanism is contained in a casing formed by the side plates 17 and Figure 1 is aperspective' view of a portion head shows a longitudinal slot 5 and 6 for re-- 18, the cover-plate 19, and the base-plate 39, which are suitably interlocked andscrewed to the woodwork'of the roll-top. Rotary tumblers 20 and 21 are provided with peripheral projections 22, Fig. 4, and are rigidly connected to sleeves 25- and26 by means of bushings 31 and 32, Fig. 3, passing through bearings in the side plates 17 and 18. The sleeves 25 and 26 are provided with screw worm-slots 27 and 28 and are rotatable-on the bolts land 2.. Pins 29 and 30, Fig. 3, enter into. slots 27 and 28, and as pins 15 and 16 are engaged by the slots 13 and 14 of the fixed plates 11 and 12, and thereby prevent rotation'ofthe bolts,

the rotary movement of the tumblers 20 and;

21 andthe sleeves25 and 26 will produce a The plates 17 and 18 of the lock-casing are connected by a pin 33, to which are fastened the outer ends of two spiral. springs 23 and 24, located between the rotary tumblers 20 and 21. The inner ends of said springs 23 and 24 are fastened at 34, Fig.5, to the abut ting ends of the two sleeves 25 and 26.

If the key, Fig. 7, is inserted into the keyhole and pressed forward, it will engage with 2 its notches the peripheral projections 22 of the rotary tumblers 20 and 21. These tumblers and their sleeves 25. and 26 will thereby be rotated, the lockingbolt-s 1 and 2 will slide longitudinally, and the bolt-heads 3 and 4 will be withdrawn from their keepers 38 in the sides of the desk. The roll-top of the desk.

may now be opened. The spiral springs 23 and 24, which have resisted the rotation of the tumblers 20 and 21 and which by the rotation of the tumblers have been tensioned, will expand again and not only return the tumblers 20 and 21 to their normal positions,

sliding movement of the locking-bolts 1 and 2.

but will also return the locking-bolts 1 and 2.

A safety device isillustrated in Figs. 8 and 9 for the purpose of preventing the picking of the lock by anyother means than the proper key. For this purpose one of the tumblersfor instance, 20, Fig. 8-is provided with a spring-blade 36, extending across the spiral springs 23 and 24 to the second tumbler 21, and a disk 35, fastened to the side 18 of the casing. The tumbler 21 is provided with notches 37, forming a single tooth with slanting sides. The disk is provided with corresponding notches 40, but forming a tooth with straight sides. As soon as it is now attempted to pick the lock by moving one of the tumblers with, for instance, a piece of wire the spring 36 will glide down'from the top of the teeth on tumbler 21 and disk 35 and will enter the notches 37 and 40, andas the disk 35 is fastened to the side 17 of the casing and cannot rotate the tumblers will become locked, and any further rotation of the same will be impossible. The tumblers 20 and 21 will then return to their normal position under the action of the spiral springs 23 and 24, and the spring-blade 36 on account of the slanting sides of notch 37 in tumbler 21 will be brought back again to its normal place on top of the teeth formed by the notches 37 and 40 on tumbler 21 and disk 35. By organizing the tumblers so that one is movable independently of the other both bolts cannot be withdrawn, even though one of such tumblers should be rotated by the insertion of a wire or analogous device. In other words, the tumblers being supported and movable separately from each other the possibility of withdrawing both bolts should the safety device for any reason fail to work is reduced to a minimum, since the successful turning of one tumbler would have no eitect upon the other.

It is claimed as new and useful- 1. In a lock, the combination with a plurality of rotary tumblers, a sleeve secured to each of the tumblers, a spiral spring connected with each sleeve and adapted to resist rotation of its tumbler, bolts shifted by said sleeves, and means carried by each bolt and having a part adapted to be rigidly secured to the closure for preventing the rotation of said bolt.

2. In a lock, the combination with a pair of sliding bolts, of rotary means, one movable independently of the other, for shifting the bolts, a movable bolt-head on oneend of each bolt, a spring controlling each bolt-head, and

means adapted to prevent the rotation of each bolt.

3. In combination with a desk-closure, sliding bolts each having a projection, rotary means for shifting the bolts, a bolt-head on one end of each bolt, a spring controlling each bolt-head, and plates rigidly secured to the desk-closu re and having slots adapted to form paths for said projections.

4. In a desk-lock, the combination with a rotary tumbler, of a spring-blade on its periphery substantially at right angles to its plane, a second tumbler, provided with notches therein having slanting sides and forming a tooth, and a stationary disk having notches and adapted to engage and prevent said springblade from further movement.

5. In a lock, the combination with a plurality of rotary tumblers, of a safety device fixedly secured to one of said tumblers, the other of said tumblers having means adapted to coact with said safety device, and a stationary member also adapted to coact with said safety device, the organization being such that on the insertion of means other than the proper key the safety device will lock all of said tumblers against rotation.

63. In a desk-lock, the combination with a pair of sliding bolts each having a projection, of a rotary sleeve on each of said bolts and provided with a cam-groove in 'Which said projection moves, a tumbler secured to each of the sleeves, one tumbler movable independently of the other, and means for preventing the rotation of one tumbler independently of the other and of both tumblers on the insertion of means other than the proper key. I

7. In a desk-lock, the combination with a pair of sliding bolts, of a rotary sleeve on each of the bolts, a tumbler secured to each sleeve, means for resisting the rotation of each tumbler, means efiective to convert the rotary motion of the sleeves into sliding motion of the bolts, and means carried by and rotatable with the tumblers and eitective to lock said tumblers against movement on the insertion of means other than the proper key.

In testimony whereof I have hereunto set my hand, in the presence of two subscribing witnesses, this 29th day of August, 1902.

ALAN ROBE FERGUSSON.

In presence of-- RALPH JULIAN SAOHERS, CECIL E. HARING. 

